I've got 4 Archimedes and 1 CDG. I like both, but I kind of give the edge to the Archimedes as well. The opinions below are my own...
Archimedes positives:
Lighter and smoother bolt lift than CDG with equivalent rate striker springs. The Archimedes being pivoting bolt handle only with no allowance in the bolt rotation for an extraction cam has shallower cocking ramps providing a lighter bolt lift. My Archimedes with a 22# striker spring has a lighter bolt lift than my CDG with the 80N/18# spring, and the 22# spring in the Archimedes provides a lot more energy to the striker hit on the primer than the 18# spring in the CDG. The CDG with the optional 100N/22.5# spring will hit the primer as hard as the Archimedes but then has a far heavier bolt lift than the Archimedes with a comparable 22# spring.
Generous bolt body to action clearance is more tolerant of dirt IMO. My CDG bolt can get slightly "draggy" coming back when dirty because the bolt body to action clearance is tighter. The negative of this extra clearance in the Archimedes is the bolt droops and flops around a bit when open and the cocking plece can rub on the top of the stock/chassis, and if your chassis has a bump/step where the cocking piece rubs it can cause a bump/hitch when running the bolt. Some say this clearance makes the bolt easier to bind when running fast, but I've never encountered that issue.
Conventional full feed ramp and standard diameter bolt without a 6 o'clock lug means the magazines sit higher in the action and this helps feeding .378" diameter cases like 223AI that can be a little tricky to get feeding smoothly in the CDG. I've got one of my Archimedes feeding 20 Vartarg out of 223 AICS magazines with zero issues... tried that combo in my CDG as a test and quickly gave up, the CDG doesn't play nice with those small diameter stubby little cartridges, lol
Rotary bolt release makes it nearly Impossible to accidently drop the bolt, you have to twist that bolt release past the detent like you mean it and it will only fully rotate to the open position in one narrow range of the bolt travel.
I prefer the larger leaf spring style extractor on the Archimedes to the pivoting claw/ball/spring arrangement on the CDG; fewer parts and no worries about dirt or debris making the extractor ball and spring sticky. They both work though.
This one will probably get some disagreement, but I like the removable scope rail on the Archimedes. Allows easy replacement for different cant or even extended rails for scopes that need extra eye relief (not sure anyone makes an extended rail, but it is possible.) I recently used one of my Archimedes for a lightweight hunting build and swapped the rail to one with less cant because the lightweight hunting scope I was using had limited elevation travel. The rail on the Archimedes is keyed to the receiver for recoil and side impact resistance and uses 5 large flathead screws to hold it down. Never had one work loose or move. I know the integral rail on the CDG will never come loose or move, but you have no option to change the cant or get an extended rail if needed.
CDG positives:
Trigger hanger allows easy trigger timing for smoothest handoff of cocking piece from cocking ramps to trigger sear.
Integral scope rail will never come loose or move, but hopefully you ordered the right cant and don't need an extended rail.
Dedicated bolt handle bias spring means the bolt handle takes much more force to pivot than the Archimedes, so in the CDG you don't feel the bolt handle pivoting while running the bolt unless you have a stuck case. Compare this to the Archimedes which uses the striker spring to also bias the bolt handle, and because of that the bolt handle pivots much easier which means you can feel it moving a bit when running the bolt quickly even if you don't have a stuck case. I wish the pivoting handle on my Archimedes was as stiff as the CDG's pivoting handle.
Toolless takedown of the bolt and a simpler bolt takedown/reassembly procedure than the Archimedes. Need a couple of tools for the Archimedes bolt. Fewer "small fiddly bits" in the CDG bolt compared to the Archimedes bolt.
Can run AW mags, can't do that in the Archimedes. AW mags are awesome if you're running a cartridge that will feed from them.
I like them both. My preference leans towards the Archimedes, especially if you're going to use it for .378" diameter cases or a cartridge that only has single stack mags available (my Archimedes are 2x 223AI, 1x 20 Vartarg, and 1x 7 PRC, so all single stack mags.) If you're running a cartridge that will feed reliably from AW mags I leans towards the CDG (my CDG is in 22GT using AW mags and works great.)
I'm disappointed, but not surprised Ted discontinued the Archimedes in favor of the CDG. Streamlining the production flow makes perfect sense, and the CDG with the action body not needing bolt lug raceway cuts like the nucleus and Archimedes it's surely quicker and cheaper to machine. That CDG is still a nice action, but I wish the Archimedes was still available as well.
